NickC
New Member
Posts:18
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| 24 Feb 2011 10:34 AM |
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Searched through the archives but no luck finding anything on this topic. Here in Chicagoland (maybe elsewhere) architects draw "wing walls" to support ground-level concrete stoops at exterior entrances. These walls extend perpendicularly from the foundation wall, out to the depth of the stoop at the top, and angle back to the base of the foundation at the bottom, giving the appearance of a "wing". There is no footing commonly associated with a wing wall. My question is- how do we form a wing wall against an ICF exterior form wall, prior to the pour?
Thanks,
Nick
Housewright Dura-Build Ltd
Algonquin, IL
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thagreen
Basic Member
Posts:283
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| 24 Feb 2011 11:22 AM |
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No base support?
Not really common for us, we've never built a wall without footers.
You here something new every day!!
I suppose you could put in an improvised ruble footing at the very least. However I'd defenetly do footing.
For connection we ussually see a specified bar size protruding in the wing and adjescent wall.
This is possible by opening up the core width and heith of block for proper adherance.
Usually we have detailed drawings for this and if we don't we contact the designer/engineer for proper bar size
and placement. |
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TexasICF
Advanced Member
Posts:622
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| 24 Feb 2011 11:25 AM |
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You might use a T-form. However, perhaps a better approach (since your up north a bit) would be to uncouple the external wing concrete from the house. This approach might require a footing for the wing. If you "make" a T-form but don't bother cutting out the foam you will thermally uncouple the external wing from the house. You might run the rebar through but if you do the rebar will conduct heat out of your house and into the wing. if you don't use rebar or concrete to connect them you might need to hold it all together with a footer. Regards. |
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thagreen
Basic Member
Posts:283
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| 24 Feb 2011 11:52 AM |
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Texas,
I'll have to disagree on this one. On most if not all plans we seen (frigid ontario) connection was specified and footers always required.
Instead of the "T" why not simply open up that whole section from top to bottom if he decides to connect.
I found that the "t" gets expensive and takes more time to install. Build the house, cut the wing connection area and build the wings. The wings will be the last of wall erection and wont affect the more time consuming build.
Ussually wings can be up in no more than a morning's work!
I do believe rebar should have no less than twice the bar diameter of concrete cover.If you've seen rebar that's been laying outside for a couple months you know exacty what I mean. |
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NickC
New Member
Posts:18
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| 24 Feb 2011 02:36 PM |
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Sorry if I mis-stated the wall description. The outside vertical edge of the wing wall angles downward back to the base of the foundation wall, forming a triangle. It doesn't require a footing because it's poured as part of the foundation wall. In standard strip-forming, there are forms made for this purpose, but they won't work with ICF. I checked with the architect and he suggested 48" long rebar bent in center at 90 degrees. These are placed in the wall about 18" on center and protrude into the stoop. The idea is to prevent frost heave of the stoop, and our building dept will accept this. Much cheaper than wing walls, and easy to do with ICF.
Thanks for the help
Nick
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thagreen
Basic Member
Posts:283
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| 25 Feb 2011 08:43 AM |
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Well that changes things,
Support the wall from underneath with a 2x proper to wall width and supports under. Also cross bracing will be required in every which way.
Cheaper yes, better ?? . Drainage will have to be carefully adressed since there's no way to prevent water from seeping under the wings. Good luck! |
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FBBP
Veteran Member
Posts:1215
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| 26 Feb 2011 11:56 PM |
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Posted By NickC on 24 Feb 2011 02:36 PM
Sorry if I mis-stated the wall description. The outside vertical edge of the wing wall angles downward back to the base of the foundation wall, forming a triangle. It doesn't require a footing because it's poured as part of the foundation wall. In standard strip-forming, there are forms made for this purpose, but they won't work with ICF. I checked with the architect and he suggested 48" long rebar bent in center at 90 degrees. These are placed in the wall about 18" on center and protrude into the stoop. The idea is to prevent frost heave of the stoop, and our building dept will accept this. Much cheaper than wing walls, and easy to do with ICF.
Thanks for the help
Nick
Nick - I suspect it is more about preventing the stoop from "stooping" i.e. residential backfill is seldom compacted enough to prevent settling. Many houses have front steps and sidewalk the are tilted after five or six years. Many prefab concrete step suppliers simple bolt concrete or metal triangles throw the wall to support the step or deck. These often result in leakage and are a little more difficult with ICF.
Another approach would be to install brick ledge just below the stoop height and pour two sono tubes out front of the house to support the outer edge. I usually thicken the front edge to form a small grade beam if the stoop is wide.
Bob |
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Jerry D. Coombs, PE
Basic Member
Posts:138
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| 02 Mar 2011 03:41 PM |
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Soils and methods vary greatly from region to region. But I have to agree with these guys on this. Any movement of the stoop, either downward from settlement or upward from frost heave, will put undue stress on the main foundation wall. I wouldn't do that most of the places I've designed.
Now I know, people will say "That's the way it's always done, and they work fine." Before you decide to go that route, go look at some that were done that way 30, 40, 50 years ago. (Maybe newer becaus the quality then is different from now.) Are they all good? Do they have any characteristics you wouldn't want? If all is well, then soils and construction methods are proven and go with it. Just be sure. |
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Jerry D. Coombs, P.E.<br>Coombs Engineering, P.C.<br>
<br>You can have with quality; You can have it fast; You can have it cheap.
Pick any two. |
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